1. Field of the Invention
The present invention relates to a waveguide system for an electrodeless lighting device, and particularly, to a waveguide system for an electrodeless lighting device which has a compact size and is capable of supplying the mostest microwave energy into a resonator.
2. Description of the Background Art
In an electrodeless lighting device, microwave power generated from an antenna of a magnetron, a power source, is transmitted to a resonator through a waveguide, and the microwave power is applied to an electrode light bulb installed in the resonator so that the light bulb radiates visible rays or ultraviolet rays. In general, its life is prolonged in comparison with a glow lamp or a fluorescent lamp, and a lighting effect thereof is excellent.
As aforementioned, in order to supply the resonator with the mostest microwave energy generated from the antenna of the magnetron, an impedance matching between the antenna of the magnetron and the waveguide or between the waveguide and the resonator should be well achieved and tuning with respect to an output frequency of the magnetron should be also well realized. Furthermore, a frequency adaptation should be satisfied depending on an impedance variation of the magnetron.
In order to satisfy aforementioned conditions, as an example for the conventional art, a three-stub tuner system has been well known, in which a length from the magnetron antenna to a slot of the waveguide is fixed by three eighth of a guided wavelength (λg) for always matching it with an arbitrary impedance of the magnetron antenna. However, because the length of a waveguide can be lengthened in the system, it is difficult to implement a compact system and there could exist many different ways for tuning a resonant frequency.
Moreover, as another example of the conventional art, a technique adopting a conductive stub in case that the length from the antenna of the magnetron to the slot of the waveguide is shorter than half of the guided wavelength (λg) is introduced in U.S. Pat. No. 5,977,712, however, it is not easy to adjust a bandwidth in the patent.